Question

A financial services company is hardening its TLS configuration. Security architects want to ensure that if an attacker later obtains the server's long-term private key, they still cannot decrypt previously captured TLS session traffic. Which cryptographic property, and its supporting mechanism, best achieves this requirement?

Accepted Answer

Perfect forward secrecy, achieved by using ephemeral Diffie-Hellman (DHE/ECDHE) key exchange

Answer

Non-repudiation, achieved by signing each session with the server's RSA private key

Answer

Confidentiality, achieved by using RSA key transport to encrypt the pre-master secret

Answer

Data integrity, achieved by applying HMAC to each record with a static shared key